St. Charles County Transportation Plan 2030 - East-West Gateway ...

B-4. Traffic Volumes
Average Daily Traffic (ADT) volume data were compiled from MoDOT, St. Charles County, and
some cities for many of the major roads in the County. They consisted of ADTs for 1990, 2000, and
2004. Since many MoDOT roads carry higher volumes, they are discussed first. A description of
each road and its traffic volumes are described below in functional classification order. A tabulation
of the traffic volumes is on Table 4. Figure 3 shows ADTs for the entire county, Figure 4 shows
ADTs for the eastern part of the county, and Figure 5 shows ADTs for the western part of the
county.
ADT’s are developed by MoDOT and most other state Department’s of Transportation (DOT’s) by
collecting 24 hour traffic counts at various times during the year. The numbers are then factored to
account for seasonal, monthly, and daily fluctuations. They are for a seven day period. Many
DOT’s also develop a weekday, Monday through Friday, traffic count termed, an AWDT. The
weekday count is always higher than the ADT since in most cases, weekend traffic counts are lower
than the weekday counts. This fact has been kept in mind throughout this report.
B-4.1. MoDOT Roads
Interstate 70 is the most traveled road in St. Charles County. It has ten lanes across the Missouri
River and carried about 165,000 vehicles a day in 2004. From the Missouri River west it loses a
lane in each direction at Fifth St. and another in each direction at Rt. 94 dropping it to six lanes. An
auxiliary lane exists between Rt. 94 and Zumbehl Rd. From there west to U.S. 40/61 it has six lanes
with some auxiliary lanes between Rt. 370 and Mid Rivers Mall Dr. and Rt. 79. Daily traffic
volumes drop from the 165,000 at the Missouri River as one moves westward to about 66,000 east
of U.S. 40/61. At the Warren County line (26.75 miles from the Missouri River) it is four lanes and
handled about 56,400 vehicles per day. For its overall length, with some segments higher and lower,
it averaged an increase of about 35 percent from 1990 to 2000 and 9 percent from 2000 to 2004.
I-64 and U.S. 40/61 carried the second highest traffic volumes across the Missouri River, about
77,500 vehicles a day in 2004. It is a seven-lane road, three lanes westbound and four lanes
eastbound, from the Missouri River to Rt. 94 and then a six-lane road from there to the end of I-64
just west of Rt. K. It then becomes U.S. 40/61 and traffic drops to about 46,100 due to the high
volumes to and from Rt. 94 and Rt. K. Segments of U.S. 40/61 at the interchanges of Winghaven
Blvd. and Lake Saint Louis Blvd. have been upgraded to Interstate standards. However, parts of the
old road remain, and full continuity of I-64 from the Missouri River to I-70 is not complete at this
time. These segments are in the Council’s TIP and it is expected that construction will be completed
within the next three years bringing it up to Interstate standards. Traffic volumes west of Rt. N are
around 35,300 and 35,700 just east of I-70. The average increase on the 13.2 miles from the
Missouri River to I-70 was about 48 percent from 1990 to 2000 and 26 percent from 2000 to 2005.
U.S. 61 is a four-lane expressway from I-70 to Lincoln County, a distance of about 7.3 miles. It has
an interchange north of I-70 with Rt. A and numerous at-grade intersections. It handles about
33,000 vehicles a day north of I-70 which stays the same to Lincoln County. The ADT on U.S. 61
increased dramatically as population in Lincoln County grew. Since 2000 it has grown about 9
percent.
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